The Food and Drug Administration on Wednesday approved Zepbound, a new weight-loss drug from drugmaker Eli Lilly that has been shown in clinical trials to help people lose up to 52 pounds in 16 months.
Zepbound is the latest addition to the powerful new drug space, which already includes Novo Nordisk’s Ozempic and Wegovy and Lilly’s Mounjaro.
The FDA approved the drug for adults who are obese or overweight with at least one weight-related condition.
In a press release, Lilly said Zepbound should be available in the U.S. by the end of the year. The list price for a month’s supply is about $1,060.
The cost could make the new drug unaffordable for many people, since insurance companies are often reluctant to cover weight-loss drugs and Medicare doesn’t legally cover them.
“The current costs are too high for the general population,” says Dr. Nishant Shah, a preventative cardiologist at Duke University Medical Center in Durham, North Carolina. “We need to be able to get to patients in an affordable way.”
In the United States, four out of ten adults suffer from obesity the Centers for Disease Control and Prevention.
Although the drug has a high price, some analysts expect it to become the best-selling drug in history.
Zepbound belongs to a class of drugs called GLP-1 agonists, which mimic a hormone that helps reduce food intake and appetite. However, Zepbound also mimics a second hormone called GIP, which, in addition to reducing appetite, can also improve the breakdown of sugar and fat in the body.
Zepbound contains the same active ingredient – tirzepatide – as Lilly’s popular diabetes drug Mounjaro.
In one Phase 3 clinical trialZepbound resulted in an average weight loss of 22.5% of body weight, or approximately 52 pounds, surpassing all weight loss medications currently on the market. Study participants had obesity or were overweight and had at least one weight-related disease.
“This is the most effective form of pharmaceutical treatment for obesity ever,” said Dr. Christopher McGowan, a gastroenterologist who runs a weight loss clinic in Cary, North Carolina.
He added that the weight loss seen from the drug was close to the weight loss from bariatric surgery.
“This is a big deal,” he said.
When it comes to whether a patient should choose between Lilly’s new drug and Wegovy, McGowan said insurance coverage and the patient’s individual response to each treatment are the most important factors to consider.
“When I talk to a patient, I will discuss both,” he said.
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However, like other drugs in its class, Zepbound carries a risk of gastrointestinal problems, including nausea, diarrhea, vomiting, constipation and stomach pain, according to the FDA.
The label doesn’t specifically mention the risk of stomach paralysis, also called gastroparesis, a more serious complication that some patients have reported as weight-loss medications become more popular. (In August, Lilly and Novo Nordisk were sued over claims that their blockbuster drugs Mounjaro and Ozempic caused stomach paralysis.)
Dr. Daniela Hurtado Andrade, an endocrinologist at the Mayo Clinic, said that while gastrointestinal problems are very common with GLP-1 drugs, most side effects do not affect a person’s quality of life.
“I’ve only had to stop taking the medication on very rare occasions,” said Andrade, who prescribes Mounjaro off-label for weight loss. “But the reality is that the majority of patients will be able to find a dose that doesn’t cause significant side effects.”
To mitigate side effects, doctors recommend patients start with a lower dose of the drug and gradually increase it over a few weeks, she said.
“Generally we increase the dose every four weeks,” she said. But “I have had patients who had to take the lowest dose for 12 weeks and then increase the second dose for another 12 weeks.”
Alexis Mitchell, 30, of Charlotte, North Carolina, was overweight for most of her 20s. Just last year, her doctor recommended Mounjaro to off-label weight loss therapy after a health crisis related to high blood pressure and prediabetes.
She started taking a weekly dose of 2.5 milligrams of Mounjaro and gradually increased this to 15 mg. She started seeing results immediately.
“It was a turning point for me,” Mitchell said. “Okay, you have to change your life now. There are no more games.”
She experienced common side effects, including nausea, constipation, migraines, stomach and body aches, but the benefits she said made the discomfort worth it.
“The weight loss 100% outweighs the side effects for me,” she said. “I lost 123 pounds in a year. I mean, I couldn’t have done it without Mounjaro.”